Commit-ID: bd922477d9350a3006d73dabb241400e6c4181b0 Gitweb: http://git.kernel.org/tip/bd922477d9350a3006d73dabb241400e6c4181b0 Author: Michael S. Tsirkin <mst@xxxxxxxxxx> AuthorDate: Thu, 28 Jan 2016 19:02:29 +0200 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Fri, 29 Jan 2016 09:40:10 +0100 locking/x86: Add cc clobber for ADDL ADDL clobbers flags (such as CF) but barrier.h didn't tell this to GCC. Historically, GCC doesn't need one on x86, and always considers flags clobbered. We are probably missing the cc clobber in a *lot* of places for this reason. But even if not necessary, it's probably a good thing to add for documentation, and in case GCC semantcs ever change. Reported-by: Borislav Petkov <bp@xxxxxxxxx> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx> Cc: Davidlohr Bueso <dbueso@xxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: virtualization <virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1453921746-16178-2-git-send-email-mst@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/include/asm/barrier.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h index a584e1c..a65bdb1 100644 --- a/arch/x86/include/asm/barrier.h +++ b/arch/x86/include/asm/barrier.h @@ -15,9 +15,12 @@ * Some non-Intel clones support out of order store. wmb() ceases to be a * nop for these. */ -#define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2) -#define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2) -#define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM) +#define mb() asm volatile(ALTERNATIVE("lock; addl $0,0(%%esp)", "mfence", \ + X86_FEATURE_XMM2) ::: "memory", "cc") +#define rmb() asm volatile(ALTERNATIVE("lock; addl $0,0(%%esp)", "lfence", \ + X86_FEATURE_XMM2) ::: "memory", "cc") +#define wmb() asm volatile(ALTERNATIVE("lock; addl $0,0(%%esp)", "sfence", \ + X86_FEATURE_XMM2) ::: "memory", "cc") #else #define mb() asm volatile("mfence":::"memory") #define rmb() asm volatile("lfence":::"memory") _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
